Clean and Sustainable Nuclear Power Srikumar Banerjee Homi Bhabha Chair Professor, Bhabha Atomic Research Centre 6 th Nuclear Energy Conclave, October.

Clean and Sustainable Nuclear Power

Srikumar BanerjeeHomi Bhabha Chair Professor,

Bhabha Atomic Research Centre

6th Nuclear Energy Conclave, October 14, 2014

World Electricity Distribution% Population not having access to electricity

20% of World population (1300 million)

25% of India’s population (300 million)

Per Capita Electricity

Consumption in kWh

Earth at night

Near-Term Energy Supply– Indian Scenario

Meeting this requirement by burning fossil fuels (Coal) would result in 3-4 billion tonnes of CO2 emission

Solution lies in enhanced deployment of primary energy sources : Solar Wind Nuclear

9% Growth

8% Growth

Renewable + hydro potential

Currently Installed Capacity ~ 220GWe

66%

12%

19%

3%

Projected Electricity Demand in 2032

Population in India in 2030 : 1.3 Billion (lower bound estimate)

Per Capita Electricity Consumption to match present world average : 2500 KWh

Total Demand of Electricity : 3250 TWh

Total Electricity Consumption in 2011-12 : 770 TWh

India needs at least 4 fold increase in electricity consumption / production in next two decades

To control Carbon foot print capacity enhancement to be targeted

Solar : 5 to 50 GW 220 TWh per year 25% capacity factor (intermittent)Wind : 15 to 50 GW

Nuclear : 5 to 60 GW 450 TWh per year 85% capacity factor

Concentrated & Continuous Source

Distributed & Intermittent Source

Primary Energy SourcesFootprint for 10 GW Installations

5000 sq.Km

400 sq.Km

1 sq.Km

Wind : 25%

Solar : 20% Nuclear : 90%

Average Capacity Factors

Conversion from fertile to fissile materials

232Th 233Th 233Pa 233U

Fertile

4.5 x 109 y2.7 barns

Fissile

238U 239U 239Np 239Pu

23.5 min22 barns

2.36 days32 barns

2.4 x 104 ya 270 b ; f 752 b

22.3 min

1500 barns1.4 x 1010 y7.37 barns

27 days20 barns

1.59 x 105 ya 47 b ; f 530 b

Fertile Fissile

n

n

Fuel cycle options

Closed Fuel Cycle

FuelFissile+Fertile

Fissile partly spent

Fertile partly converted

ReprocessingNuclear Reactor

Fertile + FissileLong lived

waste Repository

Fuel Manufacturing

FuelFissile+Fertile

Fissile partly spentFertile partly

converted

Spent Fuel Repository

Once Through Fuel Cycle

Nuclear Reactor

Huge energy potential !!

8

Adopting closed fuel cycle also reduces nuclear waste burden.

Radiotoxicity of spent fuel is dominated by :

FPs for first 100 years.

subsequently, Pu (>90%)

After Pu removal

Minor Actinides specially Am (~ 9%)

Natural decay of spent fuel radiotoxicity

With early introduction of fast reactors using (U+Pu+Am) based fuel, long term raditoxicity of nuclear waste will be reduced.

200,000 years

300 years

Attractive Features of Thorium / Thoria High Abundance

Uniformly distributed in earth crust3 to 4 times abundant than uranium

Better Fuel Performance CharacteristicsHigher melting pointBetter thermal conductivityLower fission gas releaseGood radiation resistance Dimensional stabilityBetter compatibility with coolant

Relative ease in Waste ManagementNo oxidation -Superior behavior Direct disposal in repository Generates less Pu and minor actinides

Proliferation ResistantSpent fuel difficult to divert for weapon applications

Minor actinide (g/T)

U235 + U 238

U233 + Th232

Np 900 3

Am 470 0.0018

Cm 220 0.00064

Minor Actinides in Spent Fuel

Sand containing monazite in Kerela (India) beach

Th based Fuels are attractive for both Thermal & Fast Reactors

U233 has excellent nuclear characteristics both in thermal and fast neutron spectrum.

Th is excellent host for Pu and enables deeper burning of Pu.

Using external fissile material U235, Pu or an external accelerator driven neutron source,Th-U233 cycle can be made self sustaining .

Deploying Thorium Energy: Three approaches

1. Thorium fuel in solid form in conventional reactors

2. Thorium as fuel in molten salt reactors

3. Accelerator-driven subcritical reactors using thorium fuel

KAMINI reactor in India (1996)

• 30kW experimental• U233 (20wt%)-Al fuel• Light Water Moderator

and coolant

• ThO2-PuO2 fuel • Burnup 18,400MWd/t

• UO2 fuel• Burnup 15,000MWd/t

Irradiated in Indian power reactor

Higher fission gas retention capability in ThO2 fuel

Thorium in Solid Fuel Reactor Advanced Heavy Water Reactor (AHWR)

AHWR is a 300 MWe vertical pressure tube type, boiling light water cooled and heavy water moderated reactor using 233U-Th MOX and Pu-Th MOX fuel, and Low enriched U with Th.

AHWR can be configured to accept a range of fuel types including enriched U, U-Pu MOX, Th-Pu MOX, and 233U-Th MOX in full core

Major design objectives

A large share of power from Thorium based fuel

Several passive features No radiological impact

in public domain

Passive shutdown system to address extreme threat scenarios.

Design life of 100 years.

Easily replaceable coolant channels.

Th-233U MOX

Pu-Th MOX

Inner ring:18.0% LEUO2

Middle ring: 22.0% LEUO2

Outer 22.5% LEUO2

Low Enriched Uranium (LEU)

Thorium in Molten Salt Reactor

Emergency Tanks

Heat Exchanger-1

Heat Exchanger-2

To Turbine and generator

Reactor Tank containing Fuel Salt under circulation

Reprocessing plantFission product removalAddition of fissile material

Minimal Waste : Online burning of long lived isotopes,Reduced higher Actinides

Safe : Liquid fuel, No meltdown possibility, Passive shutdown by fuel dumping

Efficient : Higher operating temperature

Thorium utilization in Accelerator driven subcritical system In a sub-critical nuclear reactor, fission neutrons supplemented by external supply of neutrons produced in a spallation reaction, High neutron yield (~20 per proton) Neutrons used for fertile to fissile conversion – Th232 to U233 (Fissile factory)

Incineration of long lived radio isotopes

Accelerator 1 GeV protonbeam

Spallation target

Subcritical reactor

Spallation reaction

15

Indian Prototype Fast Breeder Reactor

2580 1000

Fig. 4 -- PFBR FUEL PIN ASSEMBLY (all dimensions in mm)

30

Bottom Blanket

Middle Plug

Bottom End Plug

710300

10

Ø6.6

S.S.Wrapping wire

200

Spring support

Top Blanket

Fuel

5300

Top End Plug25

Spring

Core-1 (85)

Core-2 (96)

Radial Blanket (120)

SS Reflector (138)

B4C (78) -Not all shown

CSR- (9)

DSR- (3)

Core-1 (85)

Core-2 (96)

Radial Blanket (120)

SS Reflector (138)

B4C (78) -Not all shown

CSR- (9)

DSR- (3)

Core Layout

Radial Blanket (U238/Th232)

Thermal Power (MWth) : 1250Electrical output (MW): 500Fuel material : (U,Pu)O2 Coolant : Molten Sodium

Axial Blanket

U fueledPHWRs

Pu FueledFast Breeders

Nat. U

Dep. U

Pu

Th

Th

U233 FueledReactors

Pu

U233

Electricity

Electricity

Electricity

Stage 1Stage 1 Stage 2Stage 2 Stage 3Stage 3

PHWR FBTR AHWR

Thorium in the centre stage

Power generation primarily by PHWRBuilding fissile inventory for stage 2

Expanding power programmeBuilding U233 inventory

Thorium utilisation forSustainable power programme

U233

300 GWe-Year42000 GWe-Year

155000 GWe-Year

Indian Three Stage Nuclear Programme

Advanced Heavy Water Reactor (AHWR)Fast Breeder Reactor

540 MW pressurized Heavy Water reactor (PHWR)

Stage 1 : Power generation and building fissile

inventory for Stage 2

Stage 2 : Expanding power programme and building U233 inventory

Stage 3: Thorium fuel for sustainable nuclear

energy

• 2/3 energy from Thorium fuel

• Passive cooling and shutdown for safety

17

Summary

• The Closed Nuclear Fuel Cycle can be a sustainable and environmentally benign energy source which can meet the base load requirement for the entire world for several centuries

• The Thorium – Uranium 233 fuel cycle is associated with significantly reduced radiotoxicity of the nuclear waste

• For the long term sustainability of Thorium – Uranium 233 fuel cycle a sufficient inventory of fissile materials (U235 and Pu239) needs to be generated

• Spallation neutrons from high energy accelerators can augment fissile inventory and can make Thorium – Uranium 233 fuel cycle self sustaining

Paradigm ShiftBurning fossil fuel Usage of primary energy

Forest Fire

Thermal Power

Fire Stone Discovery

Wind Energy

Solar Energy

Nuclear Energy

Thank you for your attention…